ABSTRACT
The Northern United States and Canada experience winter between 4-6 months of each year and thus are more prone to experience low temperature cracking as the primary distress in their asphalt pavements. This cracking results from a sudden drop in temperature or repeated freeze and thaw cycles, causing thermal stress build-up that exceeds the asphalt pavement's tensile strength. Cracks may allow water infiltration into the pavement, causing moisture-induced damage, which reduces pavement life, and thus maintenance is required; this adds costs to the Department of Transportation (DOT). This research assesses the low-temperature cracking resistance of asphalt mixtures used in the State of Iowa by correlating the low-temperature performance of field-produced mix based on lab specifications. The disk-shaped compact tension (DCT) was used to evaluate low-temperature mixture fracture energy. From this Study, ten mixtures were found to have fracture energies ranging from 265.25J/m2 to 470J/m2 for the DCT test, where most do not meet the required fracture energy for their specified, designed levels of traffic and the minimum value of 400J/m2. Storage of asphalt as loose mixture, aging of mixture and reheating in the laboratory may have caused reduction in fracture resistance. A distress survey is recommended before the specification are revised.
